FXUS63 KGRR 040357
AFDGRR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1056 PM EST THU DEC 3 2009
LATEST UPDATE...SHORT TERM AND SYNOPSIS...
.SYNOPSIS...(1056 PM EST THU DEC 3 2009)
LOW PRESSURE WILL MOVE ACROSS LOWER MICHIGAN TONIGHT AND COMBINE
WITH COLDER AIR MOVING ACROSS LAKE MICHIGAN TO BRING THE FIRST
SNOWSTORM OF THE SEASON TO SOUTHWEST LOWER MICHIGAN. FROM 4 TO
LOCALLY 9 INCHES OF SNOW WILL BE POSSIBLE FROM HOLLAND TO MUSKEGON
AND OVER TO GRAND RAPIDS...WITH LANSING AND JACKSON GETTING LESSER
AMOUNTS. THE LOW WILL PULL EAST ON FRIDAY BUT LAKE EFFECT SNOW
SHOWERS WILL CONTINUE INTO THE WEEKEND.
&&
.SHORT TERM...(1056 PM EST THU DEC 3 2009)
(TONIGHT THROUGH SATURDAY NIGHT)
WE HAVE GONE AHEAD AND ISSUED ANOTHER UPDATE TO THE FCST...THIS TIME
TO UPGRADE THE ADVISORY FOR OTTAWA...KENT...AND MUSKEGON COUNTIES.
WE ALSO ADDED NEWAYGO TO THE ADVISORY.
WE RECEIVED A FEW REPORTS OF 5 INCHES THIS EVENING FROM NORTHERN
OTTAWA COUNTY AND 4 TO 5 INCHES IN KENT COUNTY...JUST EAST OF THE
KENT/OTTAWA BORDER. THESE LOCATIONS ONLY NEED AN INCH OR SO TO MEET
WARNING CRITERIA...WHICH SHOULD BE ATTAINABLE AS THE BAND SHIFTS
SOUTH LATER TONIGHT. THIS BAND IS STILL EXPECTED TO INCH UP INTO
SOUTHERN MUSKEGON COUNTY AND COULD DO THE SAME DAMAGE AS IT DID IN
OTTAWA COUNTY.
THE BEST LIFT WILL BE MOVING EAST WITH THE VORT MAX BY 12Z FRIDAY
BUT LES SHOWERS WILL CONTINUE THROUGH THE DAY AS MOISTURE AND
INVERSION REMAIN DEEP. ROADS SHOULD IMPROVE IN THE AFTERNOON AS AIR
TEMPS RISE TO THE LOWER 30S. ABOVE FREEZING SKIN TEMPS SHOULD ALSO
TEND TO LIMIT ACCUMS DURING THE DAY FRIDAY DESPITE INVERSION HEIGHTS
REMAINING AROUND 8 TO 10 KFT.
INVERSION SLOWLY COMES DOWN FRIDAY NIGHT AND SATURDAY MORNING AS
UPPER TROUGH FLATTENS AND SFC RIDGING BUILDS IN BY SATURDAY NIGHT.
&&
.LONG TERM...(355 PM EST THU DEC 3 2009)
(SUNDAY THROUGH THURSDAY)
THE PRIMARY FORECAST CHALLENGE IS DEALING WITH THE TIMING...
LOCATION AND OCCURRENCE OF SNOW FALL. THE MID RANGE MODELS HAVE
LARGE DIFFERENCES AND CONFIDENCE IS LOW. MAIN CHANGE TO GRIDS WAS TO
DECREASE POPS MONDAY NIGHT... AS HIGH PRESSURE RIDGES IN AND A BREAK
MAY OCCUR. OVERALL... POPS BROAD BRUSHED LATE SUNDAY NIGHT THROUGH
THURSDAY WITH AT LEAST 7/10THS CLOUD COVER.
A STRONG LOW PRESSURE SYSTEM WILL MOVE THROUGH THE CENTER OF THE
COUNTRY AROUND WEDNESDAY. THE 12Z ECMWF TAKES THE LOW OVER THE
FORECAST AREA WEDNESDAY AND THE 12Z GFS TAKES IT SOUTHEAST OF
TOLEDO. WITH NO WARMING EXPECTED OVER THE AREA... THIS SYSTEM COULD
BRING A LOT OF SNOW WITH EITHER TRACK. HOWEVER CLIMATOLOGICALLY...
OUR FORECAST AREA WOULD BE CLOSER TO THE SWEET SPOT WITH A TRACK TO
THE SOUTHEAST OF THE FORECAST AREA.
LOW TEMPERATURES WILL BE AROUND AVERAGE FOR THIS TIME OF YEAR...
WHILE HIGHS WILL BE AROUND NORMAL SUNDAY AND MONDAY AND FALL TO
BELOW NORMAL LEVELS FOR WEDNESDAY AND THURSDAY. NORMALS ARE HIGHS IN
THE MID 30S AND LOWS IN THE LOWER TO MID 20S.
&&
.AVIATION...(656 PM EST THU DEC 3 2009)
LAKE ENHANCED SNOW SHOWER ACTIVITY WILL OCCUR FOR THE EARLY PORTION
OF THE TAF PERIOD...WITH HEAVIER SNOW SHOWERS DEVELOPING FROM 03Z
ON. UNTIL 03Z...WESTERN TAFS MAY DIP IN AND OUT OF IFR WITH THE
HEAVIER SNOW BURSTS. WOULD EXPECT SOME OF THE LOWEST CIGS AND VSBYS
TO DEVELOP CLOSER TO 06Z AND THEREAFTER...WITH MODELS SHOWING LAKE
EFFECT SNOW BANDS AFFECTING MKG AND GRR IN PARTICULAR. IFR
CONDITIONS WILL LIKELY PREDOMINATE FOR THESE TERMINALS THROUGHOUT
THE OVERNIGHT AND MID MORNING HOURS. CANNOT EVEN RULE OUT LIFR FOR
MKG AND GRR AT TIMES IF HEAVY SNOW DEVELOPS BUT DID NOT INCLUDE
THOSE IN THE TAFS. VSBYS WERE BROUGHT DOWN TO 1SM BEGINNING AROUND
06Z BUT OCCASIONAL VSBYS LOWER THAN THAT ARE POSSIBLE WITH THE
HEAVIER SNOW BANDS.
A RETURN TO MVFR/VFR CONDITIONS AS PREDOMINATE WILL LIKELY HOLD OFF
UNTIL LATE MORNING/EARLY AFTERNOON FOR MKG AND GRR. THE OTHER
TERMINALS WILL LIKELY STAY MVFR FOR THE OVERNIGHT AND MORNING
HOURS...ALTHOUGH TRENDS WILL NEED TO BE MONITORED ESPECIALLY FOR
AZO. DEEPER MOISTURE IS EXPECTED TO EXIT THE AREA BY THE AFTERNOON
AND A PERIOD OF DRIER CONDITIONS AND HIGHER CIGS/VSBYS IS EXPECTED.
&&
.MARINE...(334 PM EST THU DEC 3 2009)
EXTENDED THE SMALL CRAFT ADVISORY THROUGH FRIDAY NIGHT AS WINDS AND
WAVES REMAIN HIGH...BUT BELOW GALES.
&&
.HYDROLOGY...(334 PM EST THU DEC 3 2009)
NO HYDRO ISSUES THROUGH AT LEAST EARLY NEXT WEEK AS PRECIP WILL BE
SNOW AND ANY RUNOFF WILL BE MINIMAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING FOR MUSKEGON...KENT...AND OTTAWA COUNTIES
THROUGH FRIDAY AFTERNOON.
WINTER WEATHER ADVISORY FOR NEWAYGO AND ALLEGAN COUNTIES
THROUGH FRIDAY AFTERNOON.
LM...SMALL CRAFT ADVISORY ST. JOSEPH TO MANISTEE THROUGH FRIDAY
NIGHT.
&&
$$
SYNOPSIS: OSTUNO/NJJ
SHORT TERM: OSTUNO/NJJ
LONG TERM: IOD
AVIATION: HOVING
MARINE: OSTUNO
HYDROLOGY: OSTUNO
